Stack Overflow
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Mathematics
Q&A for people studying math at any level and professionals in related fields
Proof Assistants
Q&A for mathematicians and computer scientists who develop and use proof assistants
Code Review
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MathOverflow
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Super User
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Game Development
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Physics
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Artificial Intelligence
Q&A for people interested in conceptual questions about life and challenges in a world where "cognitive" functions can be mimicked in purely digital environment
Mathematica
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Academia
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TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems